The corpses of five soldiers -- either from the Somali government army or their Ethiopian allies -- were desecrated during some of the worst clashes in the lawless capital since the interim government took over in December, witnesses said.

In one place, men dragged two semi-naked corpses by the feet while members of a crowd chanting

"God is Great" kicked and pelted them with stones, a Reuters reporter said.

In another, three bodies were hauled round by rope, kicked and then also set alight, witnesses said.

The grisly scenes recalled the aftermath of the 1993 shooting-down of a Black Hawk helicopter by Somali militiamen during a failed US operation to hunt down warlords.

Images of dead American troops being dragged through the streets of Mogadishu were the beginning of the end for a US-UN peacekeeping force which quit Somalia in 1995.

As well as the five soldiers, witnesses and medical sources said at least 11 civilians died in the clashes.

The fighting, which wounded another 81 people according to hospital staff, began early in the day when insurgents fired at Ethiopian and government forces in tanks parked at the Ministry

of Defence, residents said.

When the tanks moved out to defend their position, fighting escalated because Islamist sympathisers and clans feared they were about to be targeted in a forced disarmament drive.

Two new fighting fronts then opened up in the afternoon.

"I have never seen or experienced the kind of fighting that I saw today. People were running in all directions. I saw an old man die in front of me," said Faduma Elmi, 80.

The interim government took over Mogadishu in late December during a brief war in which it and Ethiopia routed a militant Islamist group that ruled most of south Somalia since mid-2006.

Many believe the defeated Islamists, along with disgruntled clan and warlord militiamen, are behind regular hit-and-run attacks.

In most cases, the attacks prompt retaliatory fire and civilians are often the victims of the

crossfire.

This government is the 14th attempt at establishing central rule since warlords toppled dictator Mohamed Siad Barre in 1991.

It wants to pacify Mogadishu before a planned national reconciliation conference starts on April 16.

Washington condemned the soldiers' mutilation.

"Something like that is of course a horrendous, horrendous act and we condemn it in the strongest possible terms," US envoy to Kenya Michael Ranneberger, who is also responsible for Somalia, told reporters in Nairobi.

African Union peacekeepers from Uganda are trying to help the government gain control of the anarchic Horn of Africa nation.

Like the Ethiopians, they are viewed as foreign invaders by many Somalis and are therefore also targeted.

Paddy Ankunda, AU mission spokesman, said the Ugandan soldiers were not involved in Wednesday's fighting. "It has not affected the three areas we are in," he said, referring to Mogadishu's airport, seaport and presidential palace.

Ethiopia denied its soldiers were among the five dragged through the streets.